1. Field of the Invention
Implementations consistent with the principles of the invention relate generally to mapping systems, and more specifically, to mapping systems in a digital environment.
2. Description of Related Art
Computerized mapping systems have been developed for facilitating travel planning. For example, travel-planning Internet websites are commercially available and well-known. Such websites typically permit a user to input a query with a requested location so that a map associated with the requested location may be provided to the user. Also, well-known websites allow the user to enter a start point and an end point for travel, which are then used to calculate and provide travel directions to the user.
By way of background for the detailed discussion of certain aspects of the present invention that will follow, FIGS. 1–4 depict certain aspects of an exemplary conventional digital mapping system. FIG. 1 illustrates a web browser user interface 100 that displays a map request entry web page 105. As shown, a user has entered a desired location of 353 Main St., Billings, Mont. 45619. After entering the desired location to be mapped, as shown in FIG. 1, the user then requests a map (typically from a remote server) by selecting a “Request Map” button 110. A map image is then typically generated at the remote server, transmitted to the user's computing device, and eventually displayed on the web browser user interface 100 in a map display web page.
FIG. 2 illustrates an exemplary map display web page 200 on a web browser user interface 100. Here, a map display webpage 200 displays the results of the map request from FIG. 1. The displayed information generally consists of a map image 205, which depicts the requested location and surrounding area. As shown in FIG. 2, the requested location is identified on the map image 205 by an address icon 208, and the address icon 208 is typically located in the center of map image 205. The requested location and address icon 208 may also be displayed on a map legend window 210 within map display web page 200. The address icon 208 is typically a simple two-dimensional image which, if displayed within map image 205 in close proximity with other such icons, may create visual clutter and confuse or mislead the user as to where each icon is actually pointing within map image 205.
The map webpage 200 may also display buttons or other user interface objects that may be selected to control the manner in which map image 205 is displayed. For example, as shown in FIG. 2, zoom control objects 220 are generally provided to allow the user to “zoom in” or “zoom out” and thereby affect the displayed scale of map image 205 accordingly, typically while retaining the desired location marked by address icon 208 at the center of the image. Also, direction buttons or other similar user interface objects, such as “down arrow” direction button 215, may be provided to allow the user to “pan” the image, such as by displaying more of the map information that was previously hidden because it was beyond the “southern” boundary of map image 205, while shifting and hiding a corresponding portion of the previously displayed “northern” portion of the map information. As shown in FIG. 2, such image control objects are conventionally displayed outside the boundary area of the map image 205, reducing the amount of space available for the map image 205 within the map display web page 200.
Typically, when image control objects (such as zoom control objects 200 or direction button 215 shown in FIG. 2) are selected, an HTTP request is transmitted to a server, which then transmits a new image containing the new map information to be displayed at the selected zoom level.
Specifically, in an exemplary system, as shown in FIG. 3, a web browser 300 sends an HTTP request containing location information for a requested map image to a web server 305. The HTTP request may consist of location data received via a web browser user interface 100 through a data entry web page 105, as illustrated in FIG. 1. For example, as shown if FIG. 1 and described earlier, a user may enter the following desired location to be mapped: 353 Main St., Billings, Mont., 45619. The user then requests the directions by selecting a “Request Map” button 110, and this selection event eventually causes the HTTP Request shown in FIG. 3 to be transmitted (directly or indirectly) from web browser 300 to web server 305. In response to the HTTP request, the web server 305 sends a database query (“DB Query”) to a map vectors database 310. The map vectors database 310 typically determines the corresponding vectors for the desired location data and transmits these vectors to the web server 305. The web server 305 then typically generates a bitmap image of the desired map using the received vectors, and converts the bitmap into an image format that is supported by the web browser 300 (e.g., GIF, PNG, JPEG, and the like.). The web server 305 then transmits the image to the web browser 300, generally embedding it within Hypertext Markup Language (HTML) code. The map image is then displayed to the user via the web browser user interface 100 (as shown in FIG. 2 and described earlier). Thus, when the user requests a new map view, e.g., by entering a postal address, or by clicking a navigation link next to a current map view, the web browser 300 sends to a web server 305 a request indicating the boundaries of the new map view. The web server 305 in turn extracts the corresponding vector-based map data from a database, and draws a bitmap image of the map. The web server 305 then converts the bitmap image to an image format supported by the web browser 300 and returns the image, sometimes embedded in HTML, to the web browser 300 for display to the user. Commercial implementations of such systems include AOL's MapQuest (http://www.mapquest.com), Yahoo's Telcontar-based “SmartView” maps (http://maps.yahoo.com), and Microsoft's MapPoint.net suite (e.g., http://maps.msn.com).
FIG. 4 illustrates a second exemplary system used for providing map data to a web browser. As shown in FIG. 4, a web browser 300 transmits an HTTP request to a web server 305 in the same manner that was described earlier with respect to FIG. 3. Upon receiving HTTP request from web browser 300, the web server 305 shown in FIG. 4 transmits a database query (“DB Query”) containing the requested location data to a map raster database 410. The map raster database 410 extracts the appropriate image based on the database query from among a larger pre-rendered map image. The requested image is then transmitted to the web server 305, which then transmits the image to the web browser 300 as described earlier. Thus, in a digital mapping system as shown in FIG. 4, the steps of extracting vectors and drawing a map image are replaced by simply extracting the appropriate part of a larger, pre-rendered image. Commercial implementations of such systems include Britain's MultiMaps (http://multimaps.com) and Australia's WhereIs (http://www.whereis.com.au). It should also be noted that such systems typically generate the map images from the same vector-based files that would also be used to generate printed versions of such maps.
Certain providers of digital mapping web sites have observed that some of the above problems may be overcome by transmitting a number of smaller images (known as “tiles”) from the web server 305 to the web browser 300. These smaller tiles can then be assembled by the web browser 300 into a larger image. For example Microsoft's TerraServer USA site (at http://terraserver.homeadvisor.msn.com/) currently uses a tiling approach for displaying satellite images.